Merge tag '0.4' into nightly

0.4
remove rubygems source

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
define default rake task

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
added ci configuration

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
ignore Gemfile.lock

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
added travis indicator to readme

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
version bump to 0.5

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
version bump to 0.5

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
Merge branch 'release/0.5'